Two people were injured after a semi-truck left westbound I-40 and landed on Naval Observatory Road 30-feet below early Friday morning. Ponderosa Fire officials say two people were in the cab at the time of the accident, that took place at 5:30 a.m. Both were taken to Flagstaff Medical Center, one with extensive injuries and the other person had minor injuries. The semi-truck was carrying large rolls of paper. Fire officials say Naval Observatory Road will be closed for an extended period of time while the scene is cleared and an investigation takes place. A crew from Ponderosa Fire responded to the accident, as well as State Troopers, Coconino County Sheriff’s deputies and a crew from the Flagstaff Fire Department.